Necro alert, you posted this 7 years ago: "Check that egr to lim tube that always has a crack in it around the edge by the LIM. Ok, 80% of the time. Ask me if you don't find a crack and I'll describe better where it's located."

I've had an exhaust leak for years, only when cold. When the exhaust heats up it closes up. Sounds like a single cylinder tick, like you would get from an exhaust manifold gasket leak. Probably unrelated . . .